1. Field of the Invention
The invention relates to a cylinder head assembly for an internal combustion engine. The cylinder head assembly has a housing, a plurality of elements arranged in the housing and an optical duct formed in the housing and assigned to at least one of the elements. The invention also relates to a method for measuring a temperature of an element of a cylinder head assembly of an internal combustion engine. The invention further relates to an internal combustion engine that has an engine block which has at least one cylinder and one piston.
2. Description of the Related Art
Legal regulations and customer requirements in the field of automotive engineering have led to internal combustion engines with lower consumption and increased specific engine power. Increased power densities bring about an increased thermal energy that is discharged as waste heat from the combustion chamber into the cooling system and the surroundings. This increased discharging of heat also causes an increased thermal loading of many components of the internal combustion engine. As a result, elements such as pistons, valves, cylinder head, exhaust gas manifold and turbocharger experience an increased thermal loading.
The increasing thermal loading usually is counteracted by increased cooling, structural measures and the use of higher quality materials to ensure the reliability of the engines. In this context, structural measures are generally more cost-effective, and higher quality materials are more expensive, but entail lower structural complexity.
The development of internal combustion engines therefore requires the heating of certain elements, such as valves, during real operation of the engine to be taken into account to avoid exceeding specific temperature limits. Any structural change can change the temperature of certain components during operation. Hence, the temperature of certain elements must be determined continuously in the development phase.
The temperatures of valves and certain other elements during the real operation of the engine often are determined by using materials that experience a change in material hardness as a function of temperature so that conclusions to be drawn about the operating temperatures. Thermal elements also may be integrated into certain elements of the internal combustion engine to measure temperature distributions during operation. These methods are not ideal in that the temperature measuring range is small, the measuring accuracy is low and the technical expenditure on measuring the temperature is high. Additionally, the temperature measurement can, under certain circumstances, not take place under real conditions. As a result, there is uncertainty with respect to the measured operating temperatures.
The object of the invention therefore is to provide a cylinder head assembly and a method that enables the temperature of an element to be measured precisely under real conditions.